Three terrorists who seized hostages at separate locations and ignited fear across Paris were killed Friday along with three of their hostages as the gunmen clashed with thousands of French security forces.

France’s prime minister, Manuel Valls, said the two suspects still at large in the Charlie Hebdo slayings — Cherif Kouachi, 32, and his 34-year-old brother, Said Kouachi — were known to intelligence services.

Extra officers have been stationed at various locations throughout the city, including the French Consulate, since the attack Wednesday on the Paris offices of the satirical newspaper, the Charlie Hebdo weekly.